Why does a tractor have such big tyres?

Have you ever seen a tractor working on a farm? Picture its engine going rumble, rumble. Now look at its back wheels. Their tyres are huge, much taller than you!

Car tyres are much smaller than that. So why does a tractor have such big tyres? Let's find out together.

A farmer drives the tractor out into a field. The ground there is soil, which means the soft dirt where plants grow. The farmer works right on top of it, to get the field ready for seeds.

Soil is soft and crumbly. After rain, it turns squishy. When you walk on soft soil, your shoes press little holes into it.

Here is the tricky part. A big tractor is very heavy, heavier than three cars put together. All that weight pushes down on the soft soil. What do you think would happen if the tractor had small tyres, like a car?

Small tyres would push all that weight into a few small spots. They would dig deep into the soil, deeper than your shoes ever could. The tractor would sink and get stuck in the mud!

Big, wide tyres spread the tractor's weight over lots of soil. It is like pressing on playdough. One finger pokes a deep hole, but your flat hand makes only a small dent. Big tyres work like that flat hand.

So the heavy tractor rolls on top of the soft soil instead of sinking. The farmer can drive across the whole field without getting stuck. Rumble, rumble, off it goes!

Soil. Big tyres spread the heavy tractor's weight, so it rolls on soft soil without sinking.

Next time you see a tractor rolling across a field, you will know just why its tyres are so big.