3rd grade · Science · Unit 3 of 8
Sense & Respond
How living things react
What your child practices
How people, animals and plants sense and respond to their environment: the nervous system, reflexes, special animal senses and plant responses to light, gravity and touch.
Arizona Academic Standards learning standard: 3.L1U1.5; 3.L1U1.6 · inside and outside structures of plants and animals, and how they react to the world around them
How we explain it
Children can open this short lesson before they practice.
- Your senses notice things. Nerves carry messages to your brain, and your brain tells your body what to do.
- A reflex is a quick response, like pulling your hand from something hot.
- Plants respond too: they bend toward light.
Example: A plant bends toward a window. What is it responding to? Sunlight comes through the window. Answer: light
Sense & Respond in Arizona
In the Arizona Academic Standards, this is unit 3 of 8 in 3rd grade Science, after Sound and before Adaptations & Habitats.
Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.
Source: Arizona Department of Education
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
The school bell rings. Put the steps of your response in order.
- 🏃Your muscles move you to line up
- 🧠Your brain decides what to do
- 👂Your ears sense the sound
- ⚡Nerves carry a message to your brain
Your ears sense the sound → Nerves carry a message to your brain → Your brain decides what to do → Your muscles move you to line up
Hint: Your senses notice first. Nerves carry the message to your brain, your brain decides, then your muscles move.
Question 2
A Venus flytrap snaps shut when an insect touches tiny hairs inside it. What is the stimulus?
🪰- The trap snapping shut
- The insect touching the hairs
- The soil around the roots
- The green color of the leaf
The insect touching the hairs
Hint: The stimulus is what the plant senses. The response is what the plant does.
Question 3
A shark can find a fish hiding under the sand. Which special sense helps?
🦈- Sensing tiny electric signals from the fish
- Feeling the sun's heat
- Using echoes like a bat
- Seeing right through the sand
Sensing tiny electric signals from the fish
Hint: Every animal's muscles give off tiny electric signals. Sharks have special spots on their snouts that sense them.
Question 4
Who is responding: a plant or an animal? Tap an item, then tap its basket.
Sort into: 🪴 plant · 🐾 animal
- 🐦geese fly south for the winter
- 🪟stem bends toward a sunny window
- 🍂tree drops its leaves in autumn
- 🌷flower closes up at night
- 🐇rabbit freezes when it spots a hawk
- ❄️snowshoe hare's fur turns white
🪴 plant: stem bends toward a sunny window, tree drops its leaves in autumn, flower closes up at night · 🐾 animal: geese fly south for the winter, rabbit freezes when it spots a hawk, snowshoe hare's fur turns white
Hint: Plants respond slowly, by growing, bending or dropping leaves. Animals can move their whole bodies, change their fur, or sleep through winter.
Question 5
How do bats find flying insects in the dark?
🦇- They feel the insects with their wings
- They listen for echoes of their own calls
- They follow the moonlight
- Their eyes glow like flashlights
They listen for echoes of their own calls
Hint: Bats make high-pitched sounds. The sounds bounce off insects, and bats listen for the echoes. This is called echolocation.
Question 6
Which response helps an animal survive a cold winter?
- 🦇A bat hibernates in a cave
- 🐈A cat purrs on a lap
- 🐦A bird sings in spring
- 🐕A dog chases a ball
🦇 A bat hibernates in a cave
Hint: Hibernating saves energy when food is hard to find in winter.