Easy Biology Experiments for Kids

All about Water

All living things need water; luckily, the Earth has a lot of water! Water is made up of one oxygen atom and two hydrogen atoms. This edible model of a water molecule shows the structure.

The yellow sweets represent hydrogen, and the purple sweet represents oxygen. The formula for a water molecule is H₂O.

Water is a polar molecule. It has a positive end and a negative end. The negative end of one water molecule is attracted to the positive end of another water molecule, resulting in a hydrogen bond between the two molecules. This attraction between water molecules means water has a high surface tension. There are lots of simple ways to demonstrate surface tension. An investigation using a bowl of water with pepper sprinkled over the top is good to start with.

Surface Tension Demonstration

You’ll need

A bowl of water

Ground black pepper

Washing up liquid ( dish soap )

Instructions

Fill the bowl almost to the top with tap water.

Sprinkle black paper over the surface.

Place a drop of washing-up liquid in the centre of the water.

The pepper should move very quickly to the sides.

How does it work?

The washing-up liquid reduces the surface tension of the water, which allows the water particles at the surface to spread out, taking the pepper with them!

More surface tension demonstrations

Find out how many drops of water you can fit on a coin with Rookie Parenting.

Use surface tension to make lollysticks move in water.

Try the classic magic milk experiment. Adding dish soap makes food colouring in milk explode with colour!

Enzyme Demonstrations

Organisms use enzymes to speed up chemical reactions. Enzymes are biological catalysts. The easiest way to learn about enzymes is to use them! A microorganism called yeast is used in bread making as it contains enzymes that convert sugar and starch ( from the sugar and flour in the bread mix ) into carbon dioxide and ethanol. The carbon dioxide gas makes the dough rise. Giving bread the light, airy texture we all enjoy.

Enzymes only function in the right environment for them, which is different for different enzymes. Yeast needs warm, moist conditions, which is why bread dough is left somewhere warm to rise before baking.

Learn about enzymes with pizza or bread dough

You can learn about the enzymes in yeast by making pizza or bread dough! If the dough is left somewhere cool, it won’t rise as much as dough left in a warm place, as the enzymes in the yeast won’t work as well.

Cell structure and function activities

All organisms are made up of one or more cells.

Bacteria and protozoa are examples of single-celled organisms.

A group of cells working together is called a tissue. Many tissues working together are an organ.

Cells contain organelles, which allow them to function.

Plant cell models

Making a cell model is a fun way to learn about cell structure.

You’ll need

Jelly/jello or a plate

Candy/sweets

Instructions

Make your jello as per the instructions in a lightly greased container.

When the jello is set, gently tip it into the container in which you want to make the cell.

Add sweets to look like each organelle.

Use toothpicks and stickers as signs to label the cell model.

Another idea is to combine this activity with the pizza dough to learn about enzymes and create a pizza model of a cell!

Learn more about cells, organelles and the difference between animal and plant cells with my animal and plant cell revision cards.

Specialised cells

Find out about specialised cells with a 3D model of a neurone cell.

Photosynthesis Experiments

Photosynthesis is the process by which organisms ( mostly plants ) create energy. It occurs in organelles called chloroplasts.

Carbon dioxide + water  (and light ) ———> glucose and oxygen

The energy for the reaction comes from sunlight. Photosynthesis is an essential process for life on Earth. It creates oxygen and also helps to remove the carbon dioxide created by human activity.

Plants use the glucose made during photosynthesis for cellular respiration.

Photosynthesis demonstration

Science Buddies have a great photosynthesis investigation you can try.

Plant structure and function

Dissect a flower

Dissecting a flower is a great way to learn about the different parts of a plant and their function.

You’ll need

Any flowers with large parts – lily, daffodil, tulip

Magnifying glass

White card

Tweezers

Scissors

Instructions

Lay the flowers out on a table. Try to identify the different parts.

Label areas of the different parts of a flower on a sheet of white card or paper plate and match the dissected pieces to the correct label.

Another easy way to learn about plant structure and function is to make a 3D flower model.

Osmosis Experiments

Osmosis can be a tricky concept to get your head around as it is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration. This can be demonstrated using an egg!

You might be wondering how on Earth an egg with a shell can be used to demonstrate the movement of water, and you’re right to wonder. The first thing you have to do is remove the shell by soaking the egg in vinegar. The eggshell dissolves, leaving the semi-permeable membrane behind.

You’ll need

Two eggs

Containers big enough to hold an egg

Vinegar

Water

Sugar

Instructions

Soak an egg in vinegar for 24 hours. Carefully remove the egg and rinse. You should be able to remove most of the shell. Leave it in vinegar for another 24 hours and then rinse again.

Place the egg in a cup or jar of water and leave for two hours. Water will move into the egg by osmosis as the concentration of water inside the egg is lower than outside. The egg will grow in size.

If the egg is placed in a concentrated sugar solution, water will move out of the egg into the sugar solution as the concentration of water inside the egg is greater than the sugar solution.

More Biology experiments and activities for kids

Find out why surface area to volume ratio is such an important concept in biology using sugar cubes.

Learn about Mitosis with paper plate models.

Extract your own DNA at home!

Demonstrate how diffusion works with squash or food colouring and water.

Make plasticine models of viruses to learn about their structure.

Learn about the structure of DNA with this candy model that shows the double helix structure of DNA.

Find out how trees disperse seeds with my selection of seed dispersal activities.

Model the digestive system with a pair of tights! This is an excellent way for children to really visualise how food passes through the human body.

Make a model of a pumping heart to discover why heart valves are so important.

Biology resources on the web

Learn.Genetics has lots of brilliant resources about genes, human health, neuroscience and ecology.

For younger children, check out Maddie Moate on YouTube. The channel covers topics from finding out how cinnamon grows to beekeeping, all explained in a fun and visual way.

Can you recommend any other biology experiments for kids for us to try?

Last Updated on April 12, 2023 by Emma Vanstone